Python __Slots __(制作和使用) [英] Python __Slots__ (Making and Using)

问题描述

我并没有真正上过课，可以使用__slots__使其更清晰吗?

I don't really get making a class and using __slots__ can someone make it clearer?

例如，我正在尝试创建两个类，一个是空的，另一个不是.到目前为止，我已经知道了:

For example, I'm trying to make two classes, one is empty the other isn't. I got this so far:

class Empty:
    __slots__ =()

def mkEmpty():
    return Empty()

class NonEmpty():
    __slots__ = ('one', 'two')

但是我不知道如何制作"mkNonEmpty".我也不确定我的mkEmpty函数.

But I don't know how I would make "mkNonEmpty". I'm also unsure about my mkEmpty function.

谢谢

这就是我最终得到的:

class Empty:
    __slots__ =()

def mkEmpty():
    return Empty()

class NonEmpty():
    __slots__ = ('one', 'two')

def mkNonEmpty(one,two):
    p = NonEmpty()
    p.one= one
    p.two= two
    return p

推荐答案

然后，您必须以传统方式初始化您的类.它将像这样工作:

You then have to initialize your class in a traditional way. It will work like this :

class Empty:
    __slots__ =()

def mkEmpty():
    return Empty()

class NonEmpty():
    __slots__ = ('one', 'two')

    def __init__(self, one, two):
        self.one = one
        self.two = two

def mkNonEmpty(one, two):
    return NonEmpty(one, two)

实际上，构造函数是不必要和非pythonic的.您可以并且应该直接使用类构造函数，如下所示:

Actually, the constructor functions are non-necessary and non pythonic. You can, and should use the class constructor directly, like so :

ne = NonEmpty(1, 2)

如果您需要某种记录，也可以使用空的构造函数并直接在应用程序中设置插槽

You can also use an empty constructor and set the slots directly in your application, if what you need is some kind of record

class NonEmpty():
    __slots__ = ('one', 'two')

n = NonEmpty()
n.one = 12
n.two = 15

您需要了解，仅出于性能/内存原因才需要插槽.您不需要使用它们，也可能不应该使用它们，除非您知道自己的内存有限.不过，这只应该在实际陷入问题之后.

You need to understand that slots are only necessary for performance/memory reasons. You don't need to use them, and probably shouldn't use them, except if you know that you are memory constrained. This only should be after actually stumbling into a problem though.

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